Most Obscure Gen III Facts (way out there)

Assuming you're talking about B mode, I'm wondering why you would want to do this? B mode works by spinning the ICE to create drag to slow the car down, essentially wasting energy. If you just coasted or pressed lightly on the brake pedal the car would be able to recapture some of that otherwise wasted energy increasing your fuel economy.

 

When your descending down a mountain pass, it is easier for me to pull into B mode than hold my foot on the brake. B mode maintains the car's speed on steep descents. It also works nice when I come into exit ramps off the Interstate. The battery still charges in B mode.

Mike

 

I use it for descending long downgrades to prevent the battery from becoming over-charged. Even in B mode, my battery indicates maximum SOC (which doesn't mean the battery is at 100% charge-- just at the top-end of the desired range) before reaching the bottom. Without using B mode it would hit that point much sooner, eventually followed by the activation of the friction brakes as well as spinning the engine, both in an attempt to prevent overcharging the battery.

Effective use of B mode is a planning/anticipation thing, which involves knowing the type of terrain coming-up, and the current SOC. What I would really like to have is a bias switch that would cause more of the power to be coming from the electric motors, thereby drawing-down the battery prior to a long downgrade, where I know I'm going to need the headroom to take the charge from the dynamic braking.

It does, but at a reduced rate. Using B mode is going to waste energy unless you're going to be maxing-out the battery.

 

Once the battery reaches 80% state of charge the computer will no longer charge the it at all. At that point you are basically in a modified B mode where the ICE will rev up to help slow you when you apple the brakes. (With zero charging) As far as I can tell it will use a little more friction brake, but it's not a huge difference as I have seen the RPM up to 4000rpm in "D" when in this mode going down.

In my opinion there is really no reason to ever use B mode -- you still do get a charge but it's reduced by quite a bit and a lot of wasted energy goes into spinning the engine unnecessarily. Using it when getting off the freeway means you are loosing a nice chunk of free energy going into your battery.

The way to maximize charge is to slow down without using the friction brake at all. You can see this by looking at the HSI and keeping the REGEN bar just under full. This will prevent any use of the friction brakes and you will get as much charge into your battery as possible. As you slow down you can push harder on the brake pedal without using friction. This will hold the charge at a good 80amps....

Also, for long straight grades, use cruise control as that will hold your speed (up to a point) by using regen to maintain speed. Once that fills up the battery you will get the revving ICE. No friction brakes are used and it won't light up your brake lights either.

The only time I use B is for performance driving on very right mountainous roads. B+PWR seems to give the best response it prevents the ICE from stopping every time you are slowing or going around corners so you get full power nearly instantly. This is clearly not an economical way to drive but it's responsive. The only thing that gets you in this kind of driving is you can accidentally activate brake assist with a quick but controlled jab to the brake. The ECU will apply Maximum braking even though I didn't want it ..... you have to back off the brake quite a lot to disengage the brake assist. Fortunately the stability control is decent so the car is quite composed under full braking in a corner. LOL!

 

I have scanned all the obscure facts and have not seen this one yet. For my first entry I will post something new (I think).
The steering ratio on the Prius 5 is quicker that the 2-4. I read the # of wheel turns lock to lock is ~2.5 for the 5 vs 3.5 for the Prius 2-4. I drive a 2010 prius 5 and love the steering. Can someone out there with a 2-4 confirm this?

 

This is a well-known fact, not obscure, at least to the regulars here.

 

Thanks, Eddie Haskell.

 

True. The EPS motor for the II/III/IV(2/3/4(Two/Three/Four)) has brushes. The one on the V(5/Five) is brushless.

(I'm still at a loss for what to call each 2010/2011 model.)

 

In your opinion.
In my opinion, "B" works great on down hill runs in the mountains..

 

So the steering ratio, the EPS motor, what else is technically different with the five?
Is there ia thread that is dedicated to these differences?

 

Other Prius V/Five differences from a Prius IV/Four:
1. LED headlights + foglights
2. Rear wheel well additional insulation
3. Unique shocks and springs
4. 17" rims with lower profile tires
5. Available Advance Technology Package
6. Deletes solar panel option
7. Of course, the brushless steering motor with quicker/sportier steering ratio

 

If you want to descend at a constant speed, you can also use the cruise control. If you need to slow for turns, this may not be possible. I was surprised to find that cruise makes use of regenerative braking to prevent speed increase on downhills. Driving the same roads, if I "coast" with cruise off and don't touch any pedals, the car picks up speed. With cruise engaged, it holds speed pretty well, and the hybrid system indicator can move all the way to the left side of "charge" without ever pressing the brake.

 

I almost forgot about how annoying it was to start driving off and then see the indicator light on because the hatch wasn't closed and have to get back out of my gen 2 and SLAM the hatch shut because it didn't close properly the first time. This used to happen on a regular basis. I LOVE my gen 3 - it's never ( I hope that I don't jinx myself here! ) happened on this one, and I've never slammed it shut.

 

You forgot the (useless) headlight washers.

 

Yup...forgot about those!! I wonder if the snowbirds find them more useful because apparently LEDs don't generate enough heat to melt the snow off the plastic lens.

 

Yes, I agree that coming down a mountain pass then B mode definitely makes sense... you'll likely generate more than enough power to fill the battery and still waste energy anyway and staying in control of the car is always a good thing

However, I still maintain that using it coming off exit ramps is less than ideal. The battery does still charge, but it won't charge as much as it would if you stayed out of B mode and just lightly hit the brake pedal. In that case the car would be using regen to send as much energy as possible to the battery and not trying to burn any of it off with the ICE.

It's definitely a minor point and it won't increase your fuel efficiency by huge numbers, but I still believe it is somewhat less efficient to use B mode in that case.